PROJECT SUMMARY Many children growing up in adversity experience current and future negative psychological (e.g., mental illness) and physical health (e.g., chronic disease and early mortality) outcomes. Research indicates existing interventions may aid in preventing these outcomes, mitigating their substantial societal cost. Further, several biomarkers observable in children are prospectively associated with negative health outcomes. Accordingly, this predoctoral fellowship award supports the PI?s research training in preparation for a career focused on studying the relationship between adversity, biomarkers of poor health (i.e., accelerated aging), and whether parenting can be leveraged to disrupt this relationship among at-risk children. The research project aims to significantly advance understanding of parenting behavior in the context of high levels of cumulative risk (i.e., when a family/child must cope with multiple, additive stressors). Additionally, this study will test whether improving parenting is related to improvements in biomarkers that forecast poor health outcomes, measured using two biomarkers of accelerated aging (i.e., telomere length and the epigenetic clock). This project aims to test a comprehensive conceptual model (refer to Figure 1 in the Research Strategy section) in a sample of 150 children with developmental delay who are participating in a trial testing the efficacy of a behavioral parenting intervention. This model posits that the use of an evidence-based intervention to improve parenting will disrupt the pathway between cumulative risk and biomarkers of accelerated aging. Consistent with Ecological Systems Theory, which underscores the central role of the caregiver in early childhood development, the proposed conceptual model posits that (a) higher levels of cumulative risk will be associated with accelerated biological aging and (b) improvements in parenting will ameliorate this relationship, such that higher quality parenting will disrupt the pathway between cumulative risk and accelerated biological aging. In order to provide a robust test of the conceptual model, this study will leverage an existing randomized controlled trial design as well as use a multi-informant and method framework. The proposed conceptual model will provide the necessary evidence for future work examining physical health in the context of family-based interventions in young children, and whether intervening early in development can prevent future risk of poor physical health. This study will lay the groundwork for additional longitudinal tests (i.e., longer time-frame, follow-ups later continuing later in the life span) of biological outcomes of adversity, and whether behavioral interventions influence biomarkers as well as health outcomes among at-risk, underserved families.